Galectin-1 and Galectin-3 interactors

ABSTRACT: Identification of interactors is a major attempt in cell biology. Not only protein-protein but also protein-carbohydrate interactions are of high relevance for signal transduction in biological systems. Here we aim to identify novel interacting binding partners for the β-galactoside-binding proteins Galectin-1 (Gal-1) and Galectin-3 (Gal-3) in context of the eye disease proliferative vitreoretinopathy (PVR). PVR is one of the most common failures after retinal detachment surgeries and is characterized by the migration, adhesion and epithelial-to-mesenchymal transition (EMT) of retinal pigment epithelial cells (RPE) and the subsequent formation of sub- and epiretinal fibrocellular membranes. Gal-1 and Gal-3 bind in a dose- and carbohydrate-dependent manner to mesenchymal RPE cells and inhibit cellular processes like attachment and spreading. Yet knowledge about glycan-dependent interactors of Gal-1 and Gal-3 on RPE cells is very limited, although this is a prerequisite to unravel the influence of galectins on distinct cellular processes in RPE cells. In this approach, we identified by galectin pull-down experiments and quantitative proteomic screening 131 Galectin-3 and 15 Galectin-1 interactors. They mainly play a role in multiple binding processes and are mostly membrane proteins. Here we focused on two novel identified interactors of Gal-1 and Gal-3 in the context of PVR: the low-density lipoprotein receptor LRP1 and the platelet-derived growth factor receptor beta PDGFRB. We observed crosslinking and lattice formation of exogenous Gal-1 and Gal-3 with LRP1/PDGFRB and ITGB1 on the cell surface of human RPE cells. Weaker binding of Gal-1 and Gal-3 on these interactors and no lattice formation on the cell surface was seen, when complex-type-N-glycosylation was inhibited by treatment of the cells with Kifunensine. In conclusion, the identified specific glycoprotein ligands for Gal-1 and Gal-3 give us new insights in the highly specific binding of galectins to dedifferentiated RPE cells and the resulting prevention of PVR-associated cellular events.

INSTRUMENT(S): LTQ Orbitrap XL

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell, Cell Culture

DISEASE(S): Disease Free

SUBMITTER: Jara Obermann  

LAB HEAD: Stefanie Hauck

PROVIDER: PXD005461 | Pride | 2017-06-06

REPOSITORIES: Pride